JP5934667B2 - Pipe fitting - Google Patents

Description

  The present invention relates to a pipe joint.

Conventionally, a flare joint has been widely used as a kind of pipe joint (for example, see Patent Document 1).
In general, as shown in FIG. 9, a metal pipe to be connected is formed between a tapered surface 31 of a male threaded joint body 30 and a tapered surface 34 of a cap nut 33 screwed onto a male thread 32 of the joint body 30. A flared end portion 37 formed by plastic processing of the end portion of 35 with a diameter-expanded taper is sandwiched to prevent the flare end portion 37, and is sealed by its pressure contact force.

Japanese Patent Laid-Open No. 2005-42858

  However, when the connected pipe 35 is made of aluminum, it is difficult to flare the end portion. Further, even when the connected pipe 35 is made of copper, there is a drawback that the flare processing hinders the work efficiency improvement at the piping work site. In order to avoid these problems, various pipe joint structures have been proposed. However, there are disadvantages in that the number of parts is large, complicated shaped parts are required, and labor is required during assembly.

  Therefore, an object of the present invention is to provide a pipe joint that can improve the piping work efficiency without the need to flare the end of the pipe to be connected. It is another object of the present invention to provide a pipe joint that can stably and reliably exhibit sealing performance.

Pipe joint according to the present invention, a metal fitting having a male threaded portion with the insertion tube portion having a hole for the connection pipes made of plastic composite pipe having a metal tube or a metal layer is plugged is formed in the protruding shape In a pipe joint comprising a main body and a cap nut screwed to the male thread portion of the joint body, a concave groove portion is formed on the outer peripheral surface of the insertion tube portion, and at the back of the concave groove portion It has a groove bottom thin wall portion, the distal end surface of the insertion tube portion is formed orthogonal to the axial center, and the cap nut is provided with an axial center orthogonal surface facing the distal end surface of the insertion tube portion. has inner brim portions, the uncompressed state, a inner circumferential surface smooth circumferential surface shape of the insertion tube section, when causing screwed the male screw portion of the cap nut and the fitting body, the the axis perpendicular to surface of the inner flange portion of the cap nut presses the axis-orthogonal shape of the front end face of the inserting tubular member, the upper The insertion tube receives a compressive force in the axial direction from the cap nut, so that the groove bottom thin wall portion protrudes radially inward while the width dimension of the concave groove portion is reduced. It is configured to be plastically deformed so as to bite in from the outer peripheral surface side of the inserted pipe to be connected and prevent the pipe from being connected.

Further, a metal joint body having a male threaded portion formed with an insertion tube portion having a hole into which a pipe to be connected made of a metal pipe or a plastic composite pipe having a metal layer is inserted, and the joint body And a cap nut that is screwed to the male threaded portion, and a concave groove portion is formed on the outer peripheral surface of the insertion tube portion, and a groove bottom thin wall portion is formed at the back of the concave groove portion. The insertion tube portion has a distal end surface formed orthogonal to the axial center, and the cap nut has an inner flange portion provided with an axial center orthogonal surface facing the distal end surface of the insertion tube portion. A cylindrical cover member for assisting relative rotational slippage is disposed between the inner peripheral surface of the cap nut and the outer peripheral surface of the insertion tube portion, and the cover member is formed on the insertion tube portion. In order to reduce frictional resistance by interposing between the front end surface and the axial center orthogonal surface of the inner flange of the cap nut In the uncompressed state, the inner peripheral surface of the insertion tube portion is a smooth circumferential surface, and the cap nut and the male screw portion of the joint body are screwed together in an uncompressed state. In this case, the axial center orthogonal surface of the inner flange portion of the cap nut presses the distal end surface of the insertion cylinder portion orthogonal to the axis through the inner flange portion of the cover member, and the insertion cylinder Plastically deformed into a U-shape or V-shape so that the groove bottom thin wall portion protrudes radially inward while the width of the concave groove portion decreases while the portion receives an axial compressive force from the cap nut And it is comprised so that it may cut in from the outer peripheral surface side of the said to-be-connected pipe inserted, and may prevent it.

Further, the insertion tube portion is softened in advance so as to be easily plastically deformed by compression of the cap nut .
Also, the sealing layer in advance integrally with the inner peripheral surface of the insertion tube portion is laminated, in which are configured to be sealed at the time of the bite.
In addition, a seal groove is provided on the inner peripheral surface of the insertion tube portion, and a seal material is internally provided in the seal groove.

  According to the pipe joint of the present invention, a connection (pipe) that exerts a strong pulling strength on the connected pipe and exhibits a reliable sealing performance by simply screwing the cap nut into the male thread portion of the joint body. It can be done quickly and easily. That is, there is no need to flare the end of the connected pipe, and the working efficiency is good. During compression with a cap nut, the shaft of the insertion cylinder is stably held without blurring, and the plastically deformed groove bottom thin wall part can securely bite into the outer peripheral surface side of the connected pipe and be sealed. It has excellent properties.

It is a section front view showing the uncompressed state of one embodiment of the present invention. It is a cross-sectional front view which shows a compression state. It is a principal part expanded sectional view, (A) is a principal part expanded sectional view of an uncompressed state, (B) is a principal part expanded sectional view of a compression state. It is a cross-sectional front view which shows the uncompressed state of other embodiment of this invention. It is a cross-sectional front view which shows a compression state. It is principal part sectional drawing which shows another embodiment. It is a principal part expanded sectional view, (A) is a principal part expanded sectional view of an uncompressed state, (B) is a principal part expanded sectional view of a compression state. It is the perspective view which showed various pipe joints, (A) is a perspective view of an elbow type pipe joint, (B) is a perspective view of a cheese type pipe joint, (C) is a perspective view of a socket type pipe joint. FIG. It is a sectional front view showing a conventional example.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments.
As shown in FIGS. 1 and 2, the pipe joint of the present invention is screwed into a joint body 1 having an insertion cylinder portion 4 formed in a protruding shape and having a male thread portion 2, and a male thread portion 2 of the joint body 1. A cap nut 3 and a metal connected pipe P.
The joint body 1 is made of, for example, steel, stainless steel, copper, brass, aluminum, or the like, and may be integrally formed with two or more materials as desired. The connected pipe P is made of aluminum, copper, stainless steel, or a plastic composite pipe (having a metal layer). In the present invention, “aluminum” includes an aluminum alloy, and “copper” includes a copper-based alloy. The cap nut 3 is made of steel, stainless steel, copper, brass, aluminum or the like.

The insertion cylinder part 4 has a hole 7 into which the pipe P to be connected is inserted, and a concave groove part 9 is formed on the outer peripheral surface 8 thereof. A groove bottom thin wall portion 13 is formed at the back of the recessed groove portion 9.
In FIG. 1, the insertion tube portion 4 is set to a predetermined length dimension L and is stored in the internal storage space 10 of the cap nut 3. With the screwing of the cap nut 3, the inner flange portion 3A of the cap nut 3 is in sliding contact with the insertion tube 4 is configured so as to press the tip end surface of the insertion tube 4. The number of the concave groove portions 9 is most preferably two. 1 and 2, only a part of the joint body 1 is shown (in cross section), but as a whole, as shown in FIGS. 8 (A), (B) and (C), an elbow pipe joint , Cheese-type pipe joints, socket-type pipe joints, and the like, and in FIGS. 1 and 2, the same structure may be formed at the other end of the figure. The hole portion 7 of the insertion cylinder portion 4 is formed with a bumping step portion 26 with which the distal end portion of the inserted pipe P to be inserted comes into contact.

1 and 3 (A), an uncompressed state in the middle of screwing the cap nut 3 to the male thread portion 2 of the joint body 1 is shown. 2 and 3B show a compressed state in which the insertion nut portion 4 is compressed after screwing of the cap nut 3 is completed, and the connected pipe P is connected so as not to be pulled out. Yes.
In the uncompressed state of FIGS. 1 and 3A, the inner peripheral surface 11 of the insertion tube portion 4 has a smooth circumferential surface shape.
When the cap nut 3 is turned as shown by the arrow M (see FIG. 2) and screwed into the male threaded portion 2 of the joint body 1, the uncompressed state shown in FIGS. Screw as shown in B). At this time, the previous end surface of the insertion tube 4 is subjected to compressive force F in the axial direction while sliding on the inner flange portion 3A of the cap nut 3, the groove bottom, thin-walled portion 13 width W of the groove portion 9 is declining Is plastically deformed into a U-shape or a V-shape so as to protrude radially inward. The cross-sectional shape of the concave groove portion 9 is U-shaped, and the groove bottom portion is a circular arc concave shape such as a semicircular shape. The wall thickness dimension of the groove bottom thin wall portion 13 is the smallest at the center and gradually increases in the left-right direction. Then, the plastically deformed groove bottom thin wall portion 13 bites in from the outer peripheral surface 14 side of the connected pipe P inserted in the hole portion 7 and has a pull-out resistance (has a pull-out resistance and prevents pull-out). The inner peripheral surface of the connected pipe P is also plastically deformed in the radial inward direction to form the small ridges 25. The concave groove 9 may have a width dimension W that is reduced to zero when plastic deformation occurs (that is, the side surfaces 15 are in pressure contact with each other) (not shown). That is, the insertion cylinder part 4 is compressed and plastically deformed by screwing the cap nut 3, and the length dimension L is shortened as shown in FIGS.

The insertion tube portion 4 is preferably softened in advance so as to be easily plastically deformed by compression of the cap nut 3.
As the softening treatment, for example, a method such as annealing is performed. If the material is copper or aluminum or soft steel, the softening treatment may not be necessary.
In addition, a seal groove 22 is provided on the inner peripheral surface 11 of the insertion tube portion 4, and a seal material 23 is provided in the seal groove 22.
When the insertion tube portion 4 is plastically deformed, the groove bottom thin wall portion 13 is pressure-bonded to the outer peripheral surface 14 of the connected pipe P to act as a sealing action. However, even if the sealing action by the pressure bonding of the groove bottom thin wall portion 13 is insufficient, the sealing material 23 can surely perform the sealing.

FIG. 4 shows an uncompressed state of another embodiment of the present invention. FIG. 5 shows a compressed state.
In FIGS. 4 and 5, a cylindrical cover member 24 for assisting relative rotational slippage is interposed between the inner peripheral surface 3 </ b> B of the cap nut 3 and the outer peripheral surface 8 of the insertion tube portion 4.
The cover member 24 is made of a hard metal (or hard plastic) such as stainless steel, and is preferably made of a material having a low friction coefficient. The cover member 24 includes a cylindrical portion 42 having an axial length that is slightly shorter than the length dimension L of the insertion tube portion 4 and an inner collar portion 41 that is connected to the outer end thereof. It is attached to the outside. The cover member 24 is for reducing frictional resistance (resistance due to crimping) between the inner peripheral surface 3B of the cap nut 3 and the outer peripheral surface 8 of the insertion tube portion 4 and promoting slippage, that is, relative It is provided for rotational slip promotion. According to this cover member 24, when the insertion tube portion 4 is compressed and deformed in the axial direction as the cap nut 3 is screwed, the outer diameter of the insertion tube portion 4 is increased due to the outward deformation. Thus, it is possible to prevent the cap nut 3 from being strongly pressed against the inner peripheral surface 3B. When the insertion tube portion 4 is strongly pressed against the inner peripheral surface 3B of the cap nut 3, the torque required for the operator to rotate the cap nut 3 becomes excessive, and the workability deteriorates remarkably (suddenly). The cover member 24 prevents the problem.
Note that the cover member 24 may exhibit a function of preventing the electrolytic corrosion of the cap nut 3 and the insertion tube portion 4. Furthermore, since the cap nut 3 presses the distal end surface of the insertion tube portion 4 via the inner flange portion 41 of the cover member 24, the inner flange portion 3A of the cap nut 3 and the distal end surface of the insertion tube portion 4 are pressed. It also reduces the frictional resistance (due to sliding contact) and makes it easier to slip.

6 and 7, the seal layer 12 is laminated in advance on the inner peripheral surface 11 of the insertion tube portion 4.
The seal layer 12 is formed, for example, by painting a fluororesin such as PTFE. When the cap nut 3 is screwed, the insertion tube portion 4 receives the axial compressive force F from the cap nut 3 from the uncompressed state of FIG. While the width dimension W of the groove portion 9 is reduced, the groove bottom thin wall portion 13 is plastically deformed into a U shape or a V shape so as to protrude radially inward. At this time, the plastically deformed groove bottom thin wall portion 13 is pressed from the outer peripheral surface 14 side while the inner peripheral surface 11 having the seal layer 12 is pressed against the outer peripheral surface 14 of the connected pipe P inserted into the hole 7. Encroach and prevent removal (has pull-out resistance and prevents pull-out). At the time of this biting, it is in a sealed state (by the seal layer 12). As shown in FIG. 7B, the inner peripheral surface of the pipe P to be connected is also plastically deformed in the radial inward direction to form a small convex strip 25.
In FIG. 6, the joint body 1 omits the seal groove 22 and the seal material 23, but the sealing performance can be maintained by laminating the seal layer 12 on the inner peripheral surface 11 of the insertion tube portion 4. In FIG. 6, the seal groove 22 and the seal material 23 shown in FIG. 1 and the like may be added. If it does in this way, both the sealing by the crimping | compression-bonding of the groove bottom thin wall part 13 and the sealing by the sealing material 23 can be made to act simultaneously, and a more reliable sealing effect can be anticipated.

  The design of the present invention can be changed. For example, in the embodiment shown in FIGS. 6 and 7, the cover member 24 (shown in FIG. 4 and the like) can be freely attached to the insertion tube portion 4. In addition, one or three concave grooves 9 may be provided on the outer peripheral surface 8 of the insertion cylinder portion 4.

As described above, in the pipe joint according to the present invention, the joint body 1 having the male threaded portion 2 and the joint body 1 having the insertion cylinder portion 4 having the hole portion 7 into which the pipe P to be connected is inserted, is formed. In a pipe joint provided with a cap nut 3 screwed onto one male thread portion 2, a concave groove portion 9 is formed on the outer peripheral surface 8 of the insertion tube portion 4, and a groove bottom is formed at the back of the concave groove portion 9. In the uncompressed state, the inner peripheral surface 11 of the insertion tube portion 4 has a smooth circumferential surface shape, and when the cap nut 3 and the male screw portion 2 of the joint body 1 are screwed together, The insertion cylinder part 4 receives the compressive force F in the axial direction from the cap nut 3, and the groove bottom thin wall part 13 protrudes radially inward while the width dimension W of the concave groove part 9 is reduced. Since it is configured to be plastically deformed into a letter shape and to bite in from the outer peripheral surface 14 side of the inserted pipe P to be inserted, By simply screwing the nut 3 into the male threaded portion 2 of the joint body 1, it is possible to quickly and easily perform a connection (pipe) that exerts a strong pulling resistance to the connected pipe P and exhibits a reliable sealing performance. . That is, there is no need to flare the end of the connected pipe P, and the working efficiency is good. During compression by the cap nut 3, the shaft of the insertion tube portion 4 is stably held without blurring, and the plastically deformed groove bottom thin wall portion 13 securely bites into the outer peripheral surface 14 side of the connected pipe P and is prevented from being removed. It has excellent sealing properties.
Temporarily, a U-shaped cross-section ring or a V-shaped cross-section ring of a small part is manufactured from a thin plate material, and is compressed by applying a compression force F from the axial direction while being held between two planes orthogonal to the axis. In the case of biting into the outer peripheral surface of the pipe, the posture of the cross-section collapses or abnormal plastic deformation occurs locally during the compression between the two planes perpendicular to the axis, and sealing performance (seal performance) Becomes unstable, and the pulling strength becomes unstable and insufficient. On the other hand, in the present invention, since the groove bottom thin wall portion 13 is integrally formed as a part of a sufficiently large portion (that is, the insertion tube portion 4), it is always stable even during plastic deformation. The plastic ring is deformed in a normal posture (in a normal U-shape or V-shape), and the sealing performance (sealing performance) of an annulus made of the above-mentioned thin plate material having a U-shaped or V-shaped cross section composed of small parts is not good. The present invention solves the problem of stability and the problem of unstable and insufficient pulling strength with a simple shape.

  Moreover, since the insertion cylinder part 4 is softened beforehand so that it may be easily plastically deformed by compression of the cap nut 3, the cap nut 3 can be rotated lightly with a small force, and a connection (pipe) operation | work is quicker. And easily.

  Further, since the cylindrical cover member 24 for assisting relative rotational slippage is interposed between the inner peripheral surface 3B of the cap nut 3 and the outer peripheral surface 8 of the insertion tube portion 4, the insertion tube portion 4 and the cap nut 3 are inserted. Can be prevented from being pressed strongly, and the cap nut 3 can be rotated lightly with a small force, and the connection (piping) operation can be performed more quickly and easily. The pipe connecting work can be reliably performed by holding the insertion cylinder portion 4 to be compressed and deformed in a stable posture.

  In addition, since the seal layer 12 is integrally laminated in advance on the inner peripheral surface 11 of the insertion cylinder portion 4 and is configured to be in a sealed state when biting in, the sealing performance can be improved and stabilized, and external leakage Can be prevented.

  Further, since the seal groove 22 is provided on the inner peripheral surface 11 of the insertion cylinder portion 4 and the seal material 23 is provided in the seal groove 22, the sealing performance can be improved and stabilized, and external leakage can be prevented. .

1 Joint body 2 Male thread 3 Cap nut
3A Inner flange portion 3B Inner peripheral surface 4 Insertion tube portion 7 Hole portion 8 Outer peripheral surface 9 Concave groove portion 11 Inner peripheral surface 12 Seal layer 13 Groove bottom thin wall portion 14 Outer peripheral surface 22 Seal groove 23 Seal material 24 Cover member
41 Inner flange P Connected pipe F Compressive force W Width

Claims (5)

An insertion tube portion (4) having a hole portion (7) into which a connected pipe (P) made of a metal tube or a plastic composite tube having a metal layer is inserted is formed in a protruding shape and has a male screw portion (2). In a pipe joint comprising a metal joint body (1) and a cap nut (3) screwed to the male thread part (2) of the joint body (1),
Is concave groove on the outer circumferential surface (8) (9) is formed of the insertion tube portion (4), the inner part of the concave groove (9) has a groove bottom thin wall portion (13), the insertion tube The tip surface of (4) is formed orthogonal to the axis,
Furthermore, the cap nut (3) has an inner flange portion (3A) provided with an axial center orthogonal surface facing the distal end surface of the insertion tube portion (4),
In the uncompressed state, the inner peripheral surface (11) of the insertion tube portion (4) has a smooth circumferential surface, and the cap nut (3) and the male screw portion (2) of the joint body (1) are connected to each other. When screwing, the axially orthogonal surface of the inner flange portion (3A) of the cap nut (3) presses the distal end surface orthogonal to the axial center of the insertion tube portion (4), and the insertion tube portion (4) receives axial compression force (F) from the cap nut (3), and the groove bottom thin wall (13) is radial while the width (W) of the groove (9) is reduced. It was configured to be plastically deformed into a U-shape or V-shape so as to protrude inward, and to bite in from the outer peripheral surface (14) side of the inserted pipe (P) so as to be retained. Pipe fittings characterized by An insertion tube portion (4) having a hole portion (7) into which a connected pipe (P) made of a metal tube or a plastic composite tube having a metal layer is inserted is formed in a protruding shape and has a male screw portion (2). In a pipe joint comprising a metal joint body (1) and a cap nut (3) screwed to the male thread part (2) of the joint body (1),
A concave groove portion (9) is formed on the outer peripheral surface (8) of the insertion tube portion (4), and a groove bottom thin wall portion (13) is provided at the back of the concave groove portion (9). The tip surface of (4) is formed orthogonal to the axis,
Furthermore, the cap nut (3) has an inner flange portion (3A) provided with an axial center orthogonal surface facing the tip end surface of the insertion tube portion (4). Between the peripheral surface (3B) and the outer peripheral surface (8) of the insertion tube portion (4), a cylindrical cover member (24) for assisting relative rotational slippage is disposed, and the cover member (24) Is interposed between the distal end surface of the insertion tube portion (4) and the axial center orthogonal surface of the inner flange portion (3A) of the cap nut (3) to reduce the frictional resistance. Having an inner collar part (41),
In the uncompressed state, the inner peripheral surface (11) of the insertion tube portion (4) has a smooth circumferential surface, and the cap nut (3) and the male screw portion (2) of the joint body (1) are connected to each other. When screwed, the axially orthogonal surface of the inner flange portion (3A) of the cap nut (3) is inserted into the insertion tube portion (41) via the inner flange portion (41) of the cover member (24). 4) the axially orthogonal tip surface is pressed, and the insertion tube portion (4) receives an axial compression force (F) from the cap nut (3), and the width of the concave groove portion (9). The connected pipe (P) inserted by being plastically deformed into a U shape or a V shape so that the groove bottom thin wall portion (13) protrudes radially inward while the dimension (W) decreases. A pipe joint that is configured to bite in from the outer peripheral surface (14) side and prevent it from being removed . The pipe joint according to claim 1 or 2, wherein the insertion tube portion (4) is softened in advance so as to be easily plastically deformed by compression of the cap nut (3) .   The seal layer (12) is integrally laminated in advance on the inner peripheral surface (11) of the insertion tube portion (4), and is configured to be in a sealed state at the time of the biting. Pipe fittings.   A seal groove (22) is provided on the inner peripheral surface (11) of the insertion tube portion (4), and a seal material (23) is provided in the seal groove (22). Or the pipe joint of 4.

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